Method and apparatus for air



April 15, 1,947. G, A. PEPLE, .JR

METHOD AND APPARATUS FOR AIR CONDITIONING 2 Sheets-Sheet l Original Filed Aug. 9, 1939 A. S. R... o Ts my. MM VN A A, A@ i J 55535 m April 15, 1947. G, A. PEPLE, Re. 22,870

METHOD AND APPARATUS FOR AIR-CONDITIGNING Original Filed Aug. 9, 1959 2 Sheets-Sheet 2 L ATTORNEYS Reissuecl Apr. 15, 1947 METHOD AND APPARATUS FOR AIR CONDITIONING Gustave Adolphus Peple, Jr., Richmond, Va.

Original No. 2,281,615, dated May 5, 1942, Serial No. 289,136, August 9, 1939.

Application for reissue November 2, 1944, Serial No. 561,572

' 8 Claims. 1 This invention relates to air-conditioning of rooms, auditoriums and chambers or compart- -ments generally which are adapted for human use and occupancy. More particularly this in- Ivention consists in an improved method and apparatus for the control of atmospheric conditions with marked economy oi installation vand voperation while maintaining the highest standiards of comfort and health, particularly in the :avoidance of drafts.

The primary object of my invention is to per- .mit the volume of air circulated to be varied .with the demands for heating or cooling, with resulting economies under average conditions of small demand, without adversely affecting the -ow currents of air in the rooms supplied, thus `-avoiding undesirable drafts under all conditions. An additional object is to attain the foregoing in each room supplied, while the supply to each room is varied to meet its individual demands.

The importance f maintaining a predetermined pattern of flow currents in an air-conditioned vchamber to avoid the creation of unhealthful and uncomfortable drafts has long been recognized. The customary installation of airconditioning apparatus meets this requirement by supplying to each outlet duct a constant vol- `urne of circulating air, meeting the demands for lheating or cooling by varying the temperature of the air supplied. When these demands are small, there is a great waste of energy in recirculating a large volume of air which has no .conditioning effect whatsoever. What I propose to overcome this difficulty is to provide each room with an inlet duct tted with animproved positive control, constant-velocity damper arranged to vary the volume of air admitted in response to an individual thermostat in that room. This damper maintains the ve- .locity of the air discharged through it at the predetermined rate necessary to secure the lproper throw and diffusion of the air in the room. Thus the flow pattern of the air is maintained and objectionable drafts avoided.

In order to insure that the velocity of air -passing through my improveddamper will remain constant despite variations in volume, the lstatic pressure of the air in the supply duct must be maintained constant. In order to accomplish this I control the output of the supply fan by a ystatic pressure regulator in the main supply duct Vlocated between the fan and the iirst individual groom duct. Thus the volume of air called for by the sum of the openings of the individual groom dampersaccordingto theY demands or conditioning in each room controls the volume of -air supplied to the main duct, in which the static pressure regulator insures a constant pressure behind each constant-Velocity room damper.

For a complete understanding of the method and apparatus by which the desired results are accomplished, attention is directed to the accompanying drawings and specication illustrating and describing a satisfactory embodiment of my invention, the spirit and scope which is more precisely dened in the appended claims.

In the drawings:

Fig. 1 is a horizontal section through a room duct installation showing my constant-Velocity damper and its control mechanism;

Fig. 2 is a vertical section taken on 2 2 of Fig. l;

Fig. 3 is a Vertical section taken on the lin 3 3 of Fig. l; and

Fig. 4 is a schematic diagram showing the operation of a complete installation of my invention.

Figs. 1, 2 and 3 show the construction of my positively controlled, constant-velocity damper. The room duct I3 is set into the wall Il) of the room to be conditioned and the forward face thereof is iitted with a standard grille I I with adjustable or ixed directional louvers I2. It leads from the main duct 25. Removably fastened to the duct I3 is the damper frame 24, to the top and bottom 0f which are hinged, by the hinges I5, two curved horizontal damper blades I4. The blades. I4 are so positioned that when fully open they will come as close as possible to the louvers I2. The blades I4 are curved as shown in cross-section in Fig. 3 in such a way that no matter what their position they always afford a smooth, burble-free passage for the treated air passing between them from the supply duct 2U.

The damper blades I 4 are actuated by the damper motor I6 and return spring I8 through a linkage of which I'I is the main arm. To this arm the damper blade toggle links 26 are connected by the main arm pivot link 2l and toggle pivot link 23, the pivot links 2I and 28 being adjustably connected to each other by the screw 22. By means of this screw 22 when the main arm I1 is in the fully retracted position, as shown in the drawings, the minimum opening of the damper blades I4 can be xed. The toggle pivot link the line is slidably fastened tothe guide plate 23,which is attached to the damper frame 24, and moves as it is actuated by the arm I I along the guide slot 2,5 inthe plate23.

vwith it the entire damper assembly.

The damper motor I3 is actuated by compressed air supplied to it through the pipe I9, the air pressure in which is controlled by a thermostat in the room to which the casing I3 leads from the main duct 20. Thus, when the temperature variations in that room call for increased flow. of heating or cooling air, as the case may be, the thermostat operates to increase the air pressure actuatingthe motor I6. This motor drives the arm I1 against the resistance of return spring I8, forcing open the damper blades I4 through the linkage described and admitting a greater volume of treated air.

The curvature of the blades I4 is so arranged that no matter what their position the iiow of air through them will be substantially unimpeded and its velocity will remain constant, its

volume varying proportionally to the amount of the opening, so long as the static pressure of the air in the main duct 2D is constant also. Thus, the predetermined pattern of the air flow in the room will remain substantially the same for any given setting or' the directional louvers I2 regardless of changes in the volume of air entering the room.

The damper motor I3 is supported by the plate 29 attached to the damper frame 24. The compressed air pipe I9 is fitted with the pipe coupling 21 directly behind the middle of the damper blades I4, where it is readily accessible from the front. When grille II is removed and pipe connection 21 broken, the damper frame 24 may be readily removed from the room duct I3 carrying This removal is facilitated, and irregularities in the room duct I3 compensated for, it has been found in practice, if a 1/8 inch felt strip is inserted between frame 24 and duct I3 all around, a detail not added to the drawings. The unit construction of my constant-velocity damperA greatly cheapens manufacture and facilitates installation and repair.

In Fig. 4 I show schematically the operation of my positive control, constant-velocity damper in a Working air conditioning system. In this system of my invention, the separate rooms or spaces ,to be conditioned are provided with one or more inlet grilles through which access is had to the main supply duct through a constant velocity damper assembly.

In Fig. 4, A and B represent two individual rooms having inlet ducts to them from the main supply duct through the constant-velocity damper assemblies 32a and 32h respectively. The damper motors on these assemblies are controlled by the thermostats 3Ia and 3Ib within the rooms A and B respectively. These thermostats operate to control the pressure of the air supplied to the separate room damper motors by the air sup- `ply pipes 30. In the main duct 20 between the fan and the rst individual room outlet is mounted the fan discharge damper 31. This damper is controlled by the damper motor 35 through the linkage 36. The pressure of the compressed air supplied to the damper motor 35 by the air supply pipe 30 is so regulated by the control device 34 by means of the static pressure regulator 33 located in the main duct 20 just beyond the discharge damper 31 from the fan that the static pres-sure in that duct is held substantially constant.

Thus, the operation of my system is as follows:

' Let us suppose that thermostat Bla in the room A calls for an increased supply of cooling air. This operates to open the constant-velocity damper in the assembly 32a, as herelnbefore described, increasing the volume of air discharged from the main duct 2D. This in turn would result in a lowering of the static pressure in that duct, but by operation of the static pressure regulator 33 the fan discharge damper 31 is opened sumciently to maintain a constant static pressure in duct 2li.v Thus, the velocity of air discharged through the damper assembly 32a into the room A remains the same although its volume has increased. Similarly a change in position of the damper blades in the assembly 32h because of temperature changes in the room B will aiect the static pressure in the duct 20 which in turn causes a compensating adjustment in the fan discharge damper 31.

In effect, therefore, the fan discharge damper 31 regulates the volume of air supplied to the main duct 2D in accordance with the algebraic sum of the demands of the rooms A and B or as many others as may be supplied from the duct 2'3, all the while maintaining a constant static pressure in that duct. By this means, my improved positive control, constant-velocity dampers function to maintain the flow pattern of the air discharged into the various rooms, with no objectionable drafts caused despite wide variations in the volume of air supplied. Thus in periods of low demand, a small volume of air flows through the main duct 20 with resulting economies in the operation of the system.

Certain variations that may be made in installations of my invention not shown in the precise embodiment selected for illustration will be apparent to all skilled in the art when the spirit and scope of invention as defined in the appended c`aims are understood. For example, the damper motor I6 and return spring I8 may be s0 arranged that the spring operates to keep the blades at their maximum and not minimum opening. Or the fan output control mechanism 34 regulated by the static pressure regulator 33 may operate not on the fan discharge damper 31, but on a fan intake damper, or even on the speed or pitch of the fan itself.

Moreover, it is a positive advantage of my system of air-conditioning that the various dampercontrol motors operate entirely without direct interaction of controls or motive power. The several motors, therefore, need not be driven, as I have shown, by a common source of compressed air, but instead, electrically operated damper motors may be used, greatly cheapening installation costs, particularly in existing structures.

I claim:

l. In an air-conditioning apparatus, a. duct leading into the space to be conditioned, a damper for controlling the flow of air therethrough, said damper comprising a pair of curved vanes movable toward and away from each other, means for positively and equally moving said vanes, said vanes having their convex side toward the incoming air and so positioned that a tangent to the curve at the point on each vane nearest the opposite vane is substantially parallel to the axis of the duct and the curvature of the vanes being such that the volume of air passing through the opening under constant duct pressure is at a constant velocity and substantially free from eddy currents at all positions of adjustment of said vanes, and a grill having directional louvers at the discharge end of said duct, said grill being placed as close to said damper as the necessary operating clearance of the vanes permits.

2. In air-conditioning apparatus. a. duct leading into the space to be conditioned, a damper for controlling the now of air therethrough, said damper comprising a pair of curved vanes hinged at opposite sides of said duct and movable toward and away from each other, means for positively and equally moving said vanes, said vanes having their convex side toward the incoming air and so positioned that a tangent to the curve at the point on each vane nearest the opposite vane is substantially parallel to the axis of the duct and the curvature of the vanes being such that the volume of air passing through the opening under constant duct pressure is at constant velocity and substantially free from eddy currents at all positions of adjustment of said vanes, means for supplying conditioned air to said duct and means for maintaining a constant duct pressure.

3. In air-conditioning apparatus for a plurality of rooms, a main duct, branch ducts leading to said rooms, means for supplying conditioned air to said main duct and maintaining a constant static pressure there, a damper for controlling the flow of air through each of said branch ducts, said damper comprising a pair of curved vanes hinged at opposite sides of said duct and movable toward and away from each other, means for positively and equally moving said vanes, said vanes having their convex side toward the incoming air and so positioned that a tangent to the curve at the point on each vane nearest the opposite vane is substantially parallel to the axis of the duct and the curvature of the vanes being such that a volume of air passing through the opening under constant duct pressure is at constant velocity and substantially free from eddy currents at all positions of adjustment of said vanes.

4. A damper adapted to be mounted in a passageway for gaseous fluids for controlling the iiow thereof comprising a support, a pair of curved vanes pivotally mounted on said support and movable toward and away from each other, means for positively and equally moving said vanes, said vanes having their convex side so shaped that a tangent to the curve at a point on each vane nearest the opposite vane are substantially parallel in all positions of the vanes and the curvature of the vanes being such that the volurne cf gas passing between the vanes is at conv stant velocity and substantially free from eddy currents at all positions of said vanes, when the gas pressure in said passageway is maintained constant.

5. The method of conditioning the air within a room or space which comprises supplying treated air from a source of supply to said room in a stream `of predetermined direction, maintaining said supply at a constant static pressurel positively varying the volume of treated air in said stream in response to controls located in the room so as to maintain a predetermined atmospheric condition Within the room, and malntaining the velocity and direction of the stream of treated air constant and free from eddy currents independently of the volume of air in said stream.

6. The method of controlling the temperature f the air within a room or space which comprises supplying hot or cold air as the season may require from a source of supply to said room in a stream of predetermined direction, maintaining said supply at a constant static pressure, varying the volume of air in said stream in response to controls located in the room so as to maintain a predetermined room temperature, and maintaining the velocity of the stream of air constant and free from eddy currents independently oi the volume of air in said stream.

7. The method of conditioning the air Within a plurality of rooms or spaces which comprises supplying treated air to a common ductat a constant static pressure and passing that air into the individual rooms or spaces through auxiliary ducts, regulating the volume of the streams of treated air passing through these auxiliary ducts positively in response to controls located in said rooms or spaces to maintain predetermined atmospheric conditions individually in each room .or space, and maintaining the velocity and direction of the streams of treated air constant and free from eddy currents independently of the volumes of air in said streams.

` 8. The method of controlling the temperature of the air within a plurality of rooms or spaces which comprises supplying hot or cold air as the season may require to a common duct at a constant static pressure and passing that air into the individual rooms or spaces through auxiliary ducts, regulating the volume of the streams of air passing through these auxiliary ducts positively in response to controls located in said rooms or spaces to maintain a predetermined temperature individually in each room or space, and maintaining the velocity and direction of the streams of treated air constant and free from eddy currents independently of the volumes of air in said streams.

GUSTAVE ADOLPI-IUS PEPLE, JR. 

